1. Field of the Invention
This invention relates to both a personal computer keyboard and a telecommunications instrument such as a telephone and, more particularly, to circuitry combining the functionality of the keyboard and the instrument for autonomous but interactive operation of the circuitry with the personal computer.
2. Description of the Prior Art
Personal computers (PCs) are used within an office or home environment for numerous, diverse tasks such as word processing, storage/retrieval of information from data bases, and order entry. Most personal computers receive input information originated by a typewriter-like keyboard. Each key on the keyboard that is stroked (either depressed or released) is translated to an electrical signal which, in turn, is communicated from the keyboard to the PC over a cable linking the keyboard with a specific keyboard input/output (I/O) port in the PC. Typically software loaded into the PC processes the information in a pre-programmed manner to control operation of the PC, such as by displaying the letters/numbers associated with the keystrokes on a video monitor or directing output data to a printer.
Other types of input devices, such as a mouse or light pen, may be utilized in some applications. However, in many situations, such as the entry of textual data, a typewriter keyboard is the most efficient form of providing input information. Moreover, many persons who utilize a PC in their work endeavors are frequently required to use a telephone in conjunction with, and even simultaneously with, their use of the keyboard. Telephone order takers, service bureau personnel, and operators exemplify such persons.
Conventionally, the telephone functionality and the keyboard functionality, while being co-located for accessibility by a single user, have been provided as separate, stand-alone functions. For instance, a traditional telephone instrument, composed of a handset and a base with keypad, is located proximate to the PC and especially adjacent to the keyboard; with this arrangement, a PC user may concurrently utilize the telephone instrument and the keyboard. However, the telephone instrument and the PC, including the keyboard, are electronically independent. For example, while a standard keyboard has a numerical keypad area which has a layout similar to a telephone DTMF (Dual Tone Multi-Frequency) keypad, such a numerical keypad area had conventionally never been exploited as a telephone dialer.
Recently, system developers and designers have realized the shortcomings, especially the redundancies, of separately providing keyboard and telephone functionalities, so there have been numerous disclosures of techniques for electronically integrating these capabilities.
One disclosure representative of art in this area of technology is U.S. Pat. No. 4,860,342 (issued to Danner on Aug. 22, 1989--hereinafter referred to as "Danner"). With reference to FIG. 1 herein (which is a high-level rendition of Danner's FIG. 2), there is shown system 100 for integrating telephone functionality with a PC. In particular, PC 110 serves as an interface between keyboard 120 and telephone controller 130. In turn, telephone controller 130, when activated, serves to couple incoming telephone line 132 with telephone handset/headset 135 via telephone cord 136. To paraphrase the description of Danner (particularly, column 4, lines 29`66), when the user desires to use telephone instrument 135, e.g. To initiate a telephone call, the user may depress a predetermined key on keyboard 120. Keyboard controller 121, which is a major sub component of keyboard controller 120, electronically generates and then communicates a signal indicative of the key depression activity to PC 110 via keyboard-PC cable 111; the electronic signal representative of the keyboard depression is received at PC 110 via keyboard I/O port 113. PC 110 interprets the key depression using a pre-programmed application routine executing in CPU 112 as a request to utilize telephone instrument 135. Control is then switched from the application routine to a pre-programmed control routine to interpret keystrokes which presumably will be transmitted from keyboard 120. Telephone interface circuitry 114 within PC 110 is also activated and transmits, via telephone cable 131 connected to telephone port 115, a specified activation signal to telephone controller 130. Telephone element 135 is then bridged to incoming telephone line 132, which is a standard telephone line from a switched network, such as provided by a public or private exchange access server. After the telephone connection has been established, inputs received by PC 100 from keyboard 120 are interpreted as normal telephone dialing commands, hold commands, or other telephonically related commands, rather than inputs or instructions to the application routine which was previously executing.
As further disclosed by Danner, the signals needed to execute the telephone interface control repertoire are stored in a portion of a memory (not shown) associated with the PC which is not utilized by normal application programs operating on PC 110. Consequently, when the user has completed entering the commands to the telephone portion of the PC, program control is returned to the application program which was previously executing. The application program generally does not realize that control has been wrested from it and processing of the application program will continue as if never interrupted. Meanwhile, the telephone link previously established remains activated, and conversation can continue even though PC 110 has returned to its normal mode of accepting standards-interpreted input from keyboard 120.
When the user desires to terminate or change the established telephone connection, the user may again invoke the telephone function by entering another special keystroke on keyboard 120, whereupon the telephone function software resumes control of PC 110 while the change in the telephonic function is implemented. This process of switching between application program and telephone control routine can continue indefinitely.
One other elucidating reference that relates to the system integration of both keyboard and telephone functionalities is the article entitled "Meridian M4020: Integrated terminal for today and tomorrow", authored by G. Grantham and published in the Telesis, Vol. 2, 1985 (hereinafter referred to as "Grantham"). The M4020 terminal is basically a terminal that integrates voice, text, graphics, and image capabilities into one desktop workstation. The M4020 terminal incorporates a telephone set in a base as well as a keyboard for inputting alphanumeric information, including dialing digits. However, telephone call set-ups and take-downs are not handled locally, but rather through a remotely located host processor via messages which are transferred over a Local Area Network (LAN) link. When the user lifts the handset, for example, a digital off-hook message is sent to the remote host over the LAN link. The host makes the connection internal to the host and then a message is sent to the M4020 terminal to turn on dial tone. As the telephone number is keyed on the local keyboard, the digital equivalent is sent to the host, again over the LAN link. The host, in turn, makes the connection to the public switched telephone network, and the host sends a message to notify the M4020 terminal to turn on a local speaker/microphone. The user can now hear the called party ringing signal, and the call proceeds as normal from this point. When the user hangs up, the host sends a message to the M4020 terminal clearing the previous call.
Perusal of the prior art which is represented by the above references leads to the realization that communication between the keyboard and the telephone circuitry is effected by an interposed PC or host. In the case of Danner, and similarly in Grantham, hardware and/or software routines are implemented to interrupt normal application programs to process incoming electrical signals emanating from or homing on the keyboard and to send control signals to the telephone circuitry. Thus, the interoperability of the keyboard and telephone circuitry is strictly dependent upon the interposed PC; moreover, the PC must typically be arranged with additional software and circuitry, including a telephone port to link to the external telephone controller. Thus, it is clear that the combined functionality of the keyboard and the telephone service is not independent of the PC; in fact, the PC must be powered on and executing properly to effect combined keyboard-telephone functionality. These requirements impose a severe limitation in that the desired utility of the combined functionality is totally dependent upon the operational status of the PC as well as especial adaptation or augmentation of PC hardware and software to bring about the desired combined functionality.
Thus, a need exists in the art for an autonomous arrangement which combines the functionality of the keyboard with a telephone instrument so that the arrangement may operate independently of the PC, that is, the PC need not be specially adapted to provide for the combined functionality. In a broader context, the keyboard arrangement should be locally autonomous, that is, able to function on a stand-alone basis without the intervention of a remotely located host or master processor. In addition, to offer completely independent operation, the autonomous arrangement should not even necessarily rely upon the PC for its source of power, particularly during outages of the PC.